Motor temperature sensor system and method to determine motor performance

Abstract

An electric motor system includes an electric motor, a temperature sensor mounted therein capable of measuring a local temperature and generating a temperature related signal, and a processor configured to calculate an actual temperature of a rotor magnet from the temperature related signal, and an actual output torque from the actual rotor magnet temperature. A method for determining the actual output torque of a motor includes sensing a temperature within the motor, calculating a rotor magnet temperature from the sensed temperature, and calculating the actual output mechanical torciue from the rotor magnet temperature.

1. An electric motor system comprising:
 an electric motor having at least one rotor magnet; 
 a temperature sensor mounted inside the motor capable of measuring a local temperature and generating a temperature related signal; 
 a processor configured to calculate an instantaneous temperature of the at least one rotor magnet from the temperature related signal and to calculate an instantaneous output mechanical torque of the motor from the instantaneous temperature. 
 
   
   
     2. The motor of  claim 1 , wherein the temperature sensor is mounted on a commutation board. 
   
   
     3. The motor of  claim 1 , wherein the temperature sensor is an integrated circuit type temperature sensor. 
   
   
     4. The motor of  claim 1 , further comprising:
 an analog-to-digital converter disposed between the temperature sensor and the processor. 
 
   
   
     5. The motor of  claim 4 , wherein the temperature sensor is an analog temperature sensor, wherein the analog to digital converter converts a transmitted analog temperature signal into a digital temperature signal. 
   
   
     6. The motor of  claim 1 , wherein the temperature sensor is a digital temperature sensor. 
   
   
     7. The motor of  claim 1 , wherein the processor is housed outside of the motor. 
   
   
     8. A centrifuge, comprising:
 an electric motor having at least one temperature sensor; 
 a processor that communicates with the temperature sensor to calculate an instantaneous rotor temperature and determine an instantaneous output mechanical torque generated by the motor therefrom; 
 a motor shaft; and 
 a specimen holder, connected to the motor shaft. 
 
   
   
     9. A method for determining the output mechanical torque generated by an electric motor, comprising the steps of:
 sensing a local temperature of at least one location inside the motor; 
 calculating an instantaneous rotor magnet temperature from the local temperature; and 
 calculating the instantaneous output mechanical torque generated by the motor based on the instantaneous rotor magnet temperature. 
 
   
   
     10. The method of  claim 9 , further comprising the step of:
 comparing the calculated temperature of the rotor magnet to a predetermined response temperature; and 
 adjusting an operation of the motor based on a result of the comparison. 
 
   
   
     11. The method of  claim 9 , wherein the step of sensing the local temperature at a location inside the motor is performed using temperature sensors. 
   
   
     12. A system for determining the output mechanical torque generated by an electric motor, comprising:
 means for sensing a local temperature of at least one location inside the motor; 
 means for calculating a an instantaneous rotor magnet temperature from the local temperature; and 
 means for calculating the instantaneous output mechanical torque generated by the motor based on the instantaneous rotor magnet temperature.